/Engine/Plugins/Online/OnlineSubsystem/Source/Public/OnlineSubsystemTypes.h
the stringified version of the enum passed in
namespace EOnlineDataAdvertisementType { const TCHAR * EOnlineDataAdvertisementType::ToString ( [EOnlineDataAdvertisementType::Type](API\Plugins\OnlineSubsystem\EOnlineDataAdvertisementType__Ty-) EnumVal ) }